Anyone ever notice if one way is better then the other. I tend to think the sanding would provide a bit more texture for bonding. Am I wrong. When would scrapping be preferred. Possibly on the surface instead of a finish sanding. Would it give a nicer, crisper look?
And everyone thanks for the help lately I know I've posted a lot of questions. John
My avatar is of my OldWave Oval A
Creativity is just doing something wierd and finding out others like it.
John, for best gluing the surfaces should be cleanly cut with a sharp blade, leaving a very clean and flat surface. Think of jointer or plane. When you sand a surface many of the cells and pores get filled with dust preventing complete wetting with glue.
Michael, Does this depend on the glue used? I know from personal tests that clean, scraped or jointed surfaces are best for yellow glues (like Titebond), but I always thought that hide glue and epoxy prefer some roughness to bite into. I haven't tested with these glues, and my experience is primarily with furniture-type woodwork rather than instruments. I don't know what type of surfaces urethane glues prefer either.
Even if hide glue prefers a rough texture, I would still plane the book-match joint for an instrument top or back smooth to help hide the glue line.
BTW: I've been lurking for awhile and just joined, but I wanted to comment that John's signature line is one of my favorites!
Paul Doubek
"... beauty is not found in the excessive but what is lean and spare and subtle" - Terry Tempest Williams
Welcome PaulD and thanks. Hopefully soon I can prove my signature. John
My avatar is of my OldWave Oval A
Creativity is just doing something wierd and finding out others like it.
Nearly any glue used in mandolin building works by creating a molecular bond between two surfaces. So the smoother the surface the better the bond. Some glues do have some rather strong cohesive properties which give them some strength in the mechanical bond, epoxy being one of them. But aliphatic resins and hide glue are most certianly weakened by a rough joining surface. The best surface prep you can give a joint is a pass over a perfectly set up jointing plane.
Good news is thats how I've been doing it. The jointer plane I mean. thanks all John
My avatar is of my OldWave Oval A
Creativity is just doing something wierd and finding out others like it.
What Chris Baird said.
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